aeolus - Aeolus, a synthesized pipe organ

Aeolus is a synthesised (i.e. not sampled) pipe organ emulator that
should be good enough to make an organist enjoy playing it. It is a
software synthesiser optimised for this job, with possibly hundreds of
controls for each stop, that enable the user to "voice" his
instrument. Main features of the default instrument: three manuals and
one pedal, five different temperaments, variable tuning, IDI control
of course, stereo, surround or Ambisonics output, flexible audio
controls including a large church reverb.